1. Field of the Invention
The present invention relates generally to a portable type video tape recorder (VTR), and more particularly, to a rotary head drum for a video tape recorder (VTR) which reduces the axial height of the VTR.
2. Description of the Prior Art
FIG. 1 shows an example of a tape transport assembly for loading magnetic tape around a head drum in a portable VTR according to the prior art. This tape transport assembly includes a pair of reel tables 2, a rotary head drum 3 mounted on a chassis 1 with a predetermined inclination, and a plurality of tape loading devices 4 which are movable around the rotary head drum 3. In such a tape transport assembly, a tape cassette 5 housing magnetic tape 6 is placed generally horizontally on the reel tables 2. The magnetic tape 6 is withdrawn from the tape cassette 5 by the tape loading devices 4 and then guided around the rotary head drum 37 such that video signals may be recorded on and/or reproduced from the tape by rotary heads (not shown) associated with the drum. Additionally, as shown in FIG. 1, a stationary audio head 7 is positioned adjacent to the head drum 3, for recording and/or reproducing audio signals from the tape.
Alternatively, stationary-type digital VTRs are known, primarily for professional or studio use, and which are adapted to record and/or reproduce digital signal information. In the rotary head drum used in such known stationary-type digital VTRs, a rotary disc having a multi-channel rotary head is interposed between stationary upper and lower drums, and a rotary-head driving motor is disposed below the lower drum. Although such a digital VTR is capable of high-density information recording and reproduction, a multi-channel rotary magnetic head mounted on the rotary head drum is required. As a consequence thereof, a multi-channel rotary transformer for transferring the digital signals to and from the rotary head is also required. Furthermore, the axial length of the upper drum member in such digital VTRs has been at least twice as long as that of the lower drum member in order to incorporate therein a multi-channel rotary transformer.
However, when this rotary head drum designed for use in the stationary-type digital VTR is incorporated within the conventional portable VTR shown in FIG. 1, the motor 9 disposed under the lower drum 8 secured on the chassis 1 projects below the chassis by an axial height Hl. Furthermore, the upper drum 10 which is designed to have at least twice the axial height of the lower drum projects above the magnetic tape 6 by an axial height H2. Accordingly, incorporating the known rotary head drum of the stationary-type digital VTR into the conventional portable VTR results in an unacceptably large axial height H3 of the VTR so that it is not truly or reasonably portable.